OP, I feel your pain. I should know better myself, because I had backed up all my not seen in a long time stuff to an external HDD. But THIS time, I did not (my excuse is fatigue, business, and always meaning to tomorrow), and I too lost about 2 years of stuff and series I was in the middle of watching.
However, much of my pain has been greatly relieved by the amount of the very same programming available on-line from the specific channels via Dish subscription. There are some things that aren't avaialble, but for the really important stuff I really wanted to watch, I can watch them on-line or have them downloaded to my new Hopper WS from Dish On Demand. Thank Goodness. But I shall be better about backing up in the future. .
So it turns out that only a small number of recordings on the EHD were corrupt, and it was just a coincidence that I picked two of them to transfer over to the new Hopper's DVR as my first test. The majority of files that I rescued from the old Hopper's drive are playable from the EHD and work just as well when I transfer them from the EHD to the new Hopper's internal drive.
So, I don't think the unplayable ones were corrupted when I was moving them off of the EHD. The unplayable files must've either become corrupted while in the old Hopper, or were corrupted during the transfer onto the EHD when I had the old Hopper's drive temporarily in the new Hopper.
As for the theory that the new Hopper just needs more time and then the unplayable files will work, I'm not holding out hope. It has been several days and what's unplayable is still unplayable.
I did consider doing a drive swap in the manner suggested by the last poster, but it's not my name on the account, and I'm under orders to make sure there's no funny business. So officially, neither of the Hoppers have been opened, and we made our backups on the EHD before the old Hopper died, just like you all are doing now, right?
Lol. Exactly. Granted, I don't think Dish cares as long as securities are still in place. Hell, likely more beneficial for them to not give a crap. Congrats on getting back up. If the 72 hours has passed, I wouldn't think you will see any changes. If not working at this point, to be blunt, you're sol on those recordings. But all other features should be up and running efficiently at this point.